The dakuten (Japanese: 濁点; Japanese pronunciation: [da.kɯ̥.te(ꜜ)ɴ], lit. 'muddying/voicing mark'), colloquially ten-ten (点々, "dots"), is a diacritic most often used in the Japanese kana syllabaries to indicate that the consonant of a mora should be pronounced voiced, for instance, on sounds that have undergone rendaku (sequential voicing).

The handakuten (半濁点; [han.daꜜ.kɯ̥.teɴ], lit. 'semi-muddying/voicing mark'), colloquially maru (丸, "circle"), is a diacritic used with kana for morae pronounced with /h/ or /f/ to indicate that they should instead be pronounced with /p/.

The dakuten resembles a quotation mark, while the handakuten is a small circle, similar to a degree sign, both placed at the top right corner of a kana character:

Both the dakuten and handakuten glyphs are drawn identically in hiragana and katakana scripts. The combining characters are rarely used in full-width Japanese characters, as Unicode and all common multibyte Japanese encodings provide precomposed glyphs for all possible dakuten and handakuten character combinations in the standard hiragana and katakana ranges. However, combining characters are required in half-width kana, which does not provide any precomposed characters in order to fit within a single byte.

The similarity between the dakuten and quotation marks (") is not a problem, as written Japanese uses corner brackets (「」).

The following table summarizes the phonetic shifts indicated by the dakuten and handakuten. Literally, morae with dakuten are "muddy sounds" (濁音, dakuon), while those without are "clear sounds" (清音, seion). However, the handakuten (lit. "half-muddy mark") does not follow this pattern.

(Yellow shading indicates non-standard use.)

Handakuten on ka, ki, ku, ke, ko (rendered as か゚, き゚, く゚, け゚, こ゚) represent the sound of ng in singing ([ŋ]), which is an allophone of /ɡ/ in many dialects of Japanese. They are not used in normal Japanese writing, but may be used by linguists and in dictionaries (or to represent characters in fiction who speak that way). This is called bidakuon [ja] (鼻濁音; "nasal muddy sound"). Another rare application of handakuten is on the r-series, to mark them as explicitly l: ラ゚ /la/, and so forth. This is only done in technical or pedantic contexts, as many Japanese speakers cannot tell the difference between r and l. Additionally, linguists sometimes use ウ゚ to represent /ɴ/ in cases when speaker pronounces う at the beginning of a word as a moraic nasal.